Swift - move graph related authentication defaults to graph core

[baywet]

related microsoft/kiota#1063. Graph default scope and default valid host names are present in the authentication library, which makes it more complex to use it against non-graph but MIP protected APIs.

• check that allowed host validator returns true when no hosts are provided (abstractions)
• change the default scope to be set in the get access token method to scheme://host/.default if no scopes have been provided
• remove the default hosts in the authentication library
• create derived authentication and access providers in microsoft graph core that set the default hosts
• update the documentation